Peelable puncture-resistant film for packaging
View Patent ↗A heat-sealable polymer-based multilayer film for peelable packaging comprising a polymer-based core layer having an interior-facing side and an exterior-facing side; a peelable intermediate layer on the interior-facing side of the core layer, the peelable layer having an interior-facing side and a core-facing side, and the peelable layer containing a peeling agent; and an interior skin layer on the interior-facing side of the peelable layer; wherein the core layer is polypropylene-based and contains a propylene-ethylene copolymer to impart puncture-resistance to the multilayer film.
1. A heat-sealable polymer-based multilayer film for peelable packaging comprising:
a polymer-based core layer having an interior-facing side and an exterior-facing side;
a peelable intermediate layer on the interior-facing side of the core layer, the peelable intermediate layer having an interior-facing side and a core-facing side, and the peelable layer containing a peeling agent; and
an interior skin layer on the interior-facing side of the peelable layer;
wherein the core layer is polypropylene-based and contains a propylene-ethylene copolymer to impart puncture-resistance to the multilayer film; and
wherein the multilayer film is biaxially oriented.
2. The multilayer film of claim 1 further comprising an exterior skin layer on the exterior-facing side of the core layer.
3. The multilayer film of claim 1 further comprising a functional layer on the exterior-facing side of the core layer and an exterior skin layer on said functional layer.
4. The multilayer film of claim 1 wherein the core layer has a thickness of at least about 50 μm.
5. The multilayer film of claim 1 wherein the core layer has a thickness between about 50 μm and 100 μm.
6. The multilayer film of claim 1 wherein the peelable intermediate layer has a thickness of between about 0.75 and about 3 μm.
7. The multilayer film of claim 1 wherein the interior skin layer has a thickness of between about 0.5 and about 3 μm.
8. The multilayer film of claim 1 wherein the interior skin layer contains a propylene-ethylene copolymer to impart puncture-resistance to the multilayer film.
9. The multilayer film of claim 1 wherein the core layer comprises at least 75 wt % of a homopolymer of polypropylene.
10. The multilayer film of claim 1 having a puncture load at rupture which is greater than about 1.2 kgf.
11. The multilayer film of claim 1 having a seal initiation temperature of less than about 80° C.
12. The multilayer film of claim 1 wherein the core layer comprises 75 to 90 wt % homopolymer of PP and 8 to 25 wt % of elastomer.
13. The multilayer film of claim 1 comprising:
the polymer-based core layer having the interior-facing side and the exterior-facing side;
the peelable intermediate layer on the interior-facing side of the core layer;
the interior skin layer on the interior-facing side of the peelable layer;
a functional intermediate layer on the exterior-facing side of the core layer; and
an exterior skin layer on the functional intermediate layer on the exterior-facing side of the core layer;
wherein the core layer comprises 75 to 90 wt % homopolymer of PP and 8 to 25 wt % of elastomer.
14. The multilayer film of claim 1 comprising:
the polymer-based core layer having the interior-facing side and the exterior-facing side;
the peelable intermediate layer on the interior-facing side of the core layer;
the interior skin layer on the interior-facing side of the peelable layer;
a functional intermediate layer on the exterior-facing side of the core layer; and
an exterior skin layer on the functional intermediate layer on the exterior-facing side of the core layer;
wherein the core layer comprises 75 to 90 wt % homopolymer of PP, 8 to 25 wt % of elastomer, and no more than 5 wt % non-polymer additives.
15. The multilayer film of claim 1 comprising:
the polymer-based core layer having the interior-facing side and the exterior-facing side;
the peelable intermediate layer on the interior-facing side of the core layer;
the interior skin layer on the interior-facing side of the peelable layer;
a functional intermediate layer on the exterior-facing side of the core layer; and
an exterior skin layer on the functional intermediate layer on the exterior-facing side of the core layer;
wherein the core layer consists of 75 to 90 wt % homopolymer of PP, 8 to 25 wt % of elastomer, and up to 5 wt % other components.
16. The multilayer film of claim 1 comprising:
the polymer-based core layer having the interior-facing side and the exterior-facing side;
the peelable intermediate layer on the interior-facing side of the core layer;
the interior skin layer on the interior-facing side of the peelable layer;
a functional intermediate layer on the exterior-facing side of the core layer; and
an exterior skin layer on the functional intermediate layer on the exterior-facing side of the core layer;
wherein the core layer consists of 75 to 90 wt % homopolymer of PP, 8 to 25 wt % of elastomer, and up to 5 wt % non-polymer additives.
17. The multilayer film of claim 1 comprising:
the polymer-based core layer having the interior-facing side and the exterior-facing side;
the peelable intermediate layer on the interior-facing side of the core layer;
the interior skin layer on the interior-facing side of the peelable layer;
a functional intermediate layer on the exterior-facing side of the core layer; and
an exterior skin layer on the functional intermediate layer on the exterior-facing side of the core layer;
wherein the core layer consists of 75 to 90 wt % homopolymer of PP, 8 to 25 wt % of propylene-ethylene copolymer elastomer, and up to 5 wt % other components;
wherein the multilayer film has a seal initiation temperature of less than about 80° C.
18. The multilayer film of claim 1 comprising:
the polymer-based core layer having the interior-facing side and the exterior-facing side, wherein the core layer as a thickness between 25 and 100 μm;
the peelable intermediate layer on the interior-facing side of the core layer wherein the peelable intermediate layer comprises a blend of propylene polymer and ethylene polymer and a peeling agent, wherein the peelable intermediate layer has a thickness between 0.5 and 6 μm;
the interior skin layer on the interior-facing side of the peelable layer, wherein the interior skin layer has a thickness between 0.25 and 6 μm;
a functional intermediate layer on the exterior-facing side of the core layer, wherein the functional intermediate layer on the exterior-facing side of the core layer layer has a thickness between 0.5 and 6 μm; and
an exterior skin layer on the functional intermediate layer on the exterior-facing side of the core layer, wherein the exterior skin layer has a thickness between 0.25 and 6 μm;
wherein the core layer consists of 75 to 90 wt % homopolymer of PP, 8 to 25 wt % of propylene-ethylene copolymer elastomer having a melt flow rate of 2 to 10 dg/min and a total crystallinity of 5% to 10%, and up to 5 wt % other components.
19. A package for crackers comprising a cardboard box and a bag within the box wherein the bag comprises the multilayer film of claim 1 .
20. The package of claim 19 wherein the multilayer film comprises:
the polymer-based core layer having the interior-facing side and the exterior-facing side;
the peelable intermediate layer on the interior-facing side of the core layer;
the interior skin layer on the interior-facing side of the peelable layer;
a functional intermediate layer on the exterior-facing side of the core layer; and
an exterior skin layer on the functional intermediate layer on the exterior-facing side of the core layer;
wherein the core layer consists of 75 to 90 wt % homopolymer of PP, 8 to 25 wt % of propylene-ethylene copolymer elastomer, and up to 5 wt % other components.